Testing recurring subscriptions in a new release in both development environment and in Test Flight, we see an increased percentage of failed calls returning from Apple server. The return failure message is that an unknown error occurred.
The behavior is not consistent and most often we get a failure and another attempt succeeds. We do get around 50% failures which is alarming and cannot be explained to the end user.
We have also experimented with previous test versions that are in production currently and we see the same behavior, so this is not isolated to the most recent release we plan nor to a specific application we have. Past testing in previous releases did not return such high percentage of failures from Apple server.
Have you encountered such an issue? We have no idea what may cause Apple server to return with this "Unknown error" and there is no log we can consume from Apple subscription service. Appreciate your help on this.
There was an App Store-Sandbox outage that is now resolved. Please try again and let us know if the issue still persists.